Device for measuring color and light densities



R. MACKAY June 14, 1938.

2 Sheets-Slxxeet 1 DEVICE FOR MEASURING 001403 AND LIGHT DENSITIES Filed March' 25,v 1935 June 14 1938. R, MAQKAY 2,120,499

DEVICE FOR MEASURING COLOR AD LIGHT DENSITIES Filed March s, 19:55 v 2 sheets-sheet 2 80 o 62 F17 4 6,2 W

a A u ./,7 W gz n f i 62a [Wh 36 b 65a 65' u) 1| f' il f IL 'l t i l f) I ll @e SZ Z0 69 6/2 I }i` l f v Ylv w I\` g1 I n I e f o: l 50' e l I l Zz i v g Z5 i zz Z6 l I A 29 59 y I g z Y l l 4 l l, g a g l 51 Jrzd'enor 21 Rober? Macway Patented June 14, v1938 UNITED STATES PATENT OFFICE DEVICE FOR MEASURING COLOR AND l LIGHT DENSITIES Robert Mackay, Chicago, Ill. Application March 25, 1935, Serial No. 12,795

7 Claims.

- sought to be reproduced in the photoengraving,

photogravure, lithographing and oil-set color printing arts. My invention further relates to novel apparatus for quickly and eiilciently using and applying novel combination of various steps to commercially reproduce photoengraving, rotogravure, lithographing and other color printing plates as will be more specifically described hereinafter.

My invention has for its object to provide apparatus for analyzing and determining to an accurate degree the density of a single color or of different colors in a given area of a Work of art which is sought to be commercially reproduced by any one of the commercial methods used in the graphic arts, the deilnite result of such analysis and determination enabling the operator or color finisher to make the plates, half tones, or other like reproduction units, used in the reproduction process, correctly and oi' the proper dot structure.

A` further object of my invention is the provision of apparatus permitting carrying cut of ,a

process for use in connection with either relief printing, or rotogravure processes or rotogravure reproduction which will immediately and accurately indicate to the operator and user, not only the individual density of a. combination of superposed colors of a given area on a given work of art to be reproduced, but will also accurately indicate the density of the negative and positive which should be employed in the making ci each individual printing plate or other plate (one plate being made for each color and the successive imprinting superposed) in order to have the resultant commercially reproduced picture or other work of art of the same matched and identical color blends and color density; as the original worl: of art being reproduced, thus insuring identical reproduction in the photographic, rotogravure or otherwise commercially reproduced copies. I

A further object of my invention is the provision of devices providing means for analyzing and determining the density of an individual color or of a plurality of superposed colors borne by a Work of art and simultaneously determining the size of the dot structure which yit is (ci. six-14) necessary to employ inl order` to imprint a plu` rality of such superposed colors so that the copies reproduced from the respective plates. the plates being printed successively, will be identical in shading, color blend, light eirects, etc., to that of the original work of art sought to be reproduced.

A further object of my invention lis the provision of an inexpensive and easily operable device which includes a plurality of color bands, each band being composed of a plurality oi' color areas all of the same primary color and each area being of a different and uniformly colored density, and wherein each of said primary color bands is movably mounted and arranged so that portions thereof are superposed; so that any two or more combinations of color areas may be quickly and easily presented to the viewer for comparison with the area of the original work of art sought to be reproduced, and wherein uniformly scaled indicia are simultaneously presented to the viewer for indicating the respective density of color areas presented to the viewer at a given time.

A further object of my invention is the provision of a manually operable device which includes a plurality of movably mounted color bands, each color band comprising a plurality of substantially adjacent areas, each area being ofl a diierent color density of thebasic primary color represented bythe band as a whole, in combination with indiciafor simultaneously indicating to the viewer at a remote point from the viewing window the density of either one or a plurality of color areas which are presented in adjacent position to the viewer, thereby enabling the viewer and operator to accurately match given areas of a work of art sought to be reproduced.

A further object of my invention is the provision of a device wherein a plurality of primary color bands are movably mounted for superposed adjacent presentation to a viewing window and artificial lighting means on the side of said bands opposite to the viewer, for the purpose of en'- abling the viewer to rst match the color density or lightdensity of a work of art being reproduced and immediately presenting indicia indiin addition to showing the actual proportions of colors required to make the selected color sought to be reproduced, such negatives andpositives being usable in intaglio printing and printing processes which require use of a continuous tone negative and continuous tone positive.

Other and further important objects of my invention will be apparent from the following description and claims.

This invention (in a preferred form) is illustrated in the following specification and claims.

On the drawings:

Fig. 1 is a side elevational view of my color and light analyzing device with the upper portion of the front panel thereof broken away to show the interior structure.

Fig. 2 is a cross sectional view taken on line 2-2 of Fig. 1. 'y f Fig. 3 is a side elevational view of my device. with the entire front panel and viewing windows removed and showing the relative position of the primary color bands and other parts.

Fig. 4 is a side elevational view with parts broken away on line 4-4 of Fig. 2 and showing the primary color bands from the rear thereof.

The reference numeral lil indicates a rectangular cabinet having removable front panel II and a removable rear panel I2, each of which is preferably secured to said cabinet I by means of suitable screws I3 and i4 respectively as shown in the drawings, particularly Fig. 2, and the removal of the front and rear panels permits access to the interior of the cabinet Ill. Said cabinet may be made of wood or metal or other suitable non-transparent material.` As shown in cross section in Fig. 2 the top and bottom of the cabinet I0 respectively have opposed longitudinally extending grooves at points which may be-made of frosted glass having an substantially midway between the front and back of said cabinet, said grooves receiving and removably retaining therein the opposite upper and lower edges of a light filtering panel I5 opaque or corrugated surface which will diiuse and lter light from ,one side to the other there-v of, thereby forming a rear compartment I6 as clearly shown in Fig. 2. Mounted by screws I1 von the inside surface of the bottom of the cabinet is a suitable light bulb-receiving socket I6 which may be of conventional construction and which is connected to source of electric current by wires indicated by reference numeral J6. An electric light bulb 20 of the desired voltage is removably mounted `in said socket I6 in a conventional manner.

As shown in Fig. 1, a'plurality of rectangular apertures are formed in front panel Il in parallel substantially uniformly spaced apart relation and in a row substantially midway between the upper and loweredges of said front panel II. As indicated in Fig. 1 the nrst four apertures from the left are indicated by the referencenumerals 2|, 22, 23 and 24 respectively. The fifth aperture and hereinafter designated the viewing window is indicatedby the reference numeral 25. To .the right of the viewing window 25 are parallelspaced apart rectangular apertures 26,.

21, 23, 26, 36, 3i, 32 and 33 respectively, all for a purpose more fully explained hereinafter. Im-

mediately rearward and adjacent the inside surface of `panel II is a clear glass panel 34 which extends from one end of thecabinet to the other and which forms a vclosure and window for each of thel aforesaid rectangular apertures as clearly 'inet on the outside of the cabinet.

shown in Figs. 1 and 2, said glass panel 34 being' suitably secured in such described position.

A pluralityof horizontal rotatable shafts 35, 36, 31 and 38 respectively; preferably four in number, are mounted in vertical alinement and for rotative engagement with respect to said cabinet I0, one end of each of said shafts terminating immediately adjacent one end of said cabinet I0 (at right of Fig. 1) and being suitably journaled for rotative engagement in suitable apertured bushings 39, 40, 4I and 42 respectively. The opposite end of each of said shafts is suitably journaled in bushings 43, 44, 45 and 46 respectively, which in turn are mounted in convenient manual and selective rotation of said shafts at will.

A plurality of horizontal shafts, preferably four in number, indicated by reference numerals 5I,

52, 53 and 54, are mounted in parallel spaced f apart relation and in vertical alignment in the lower part of said cabinet I0, one end of each said shafts (at left of Fig. l) being suitably journaled for -rotative engagement in bushings 55, 56, 51 and 58, which in turn are suitably mounted in one end of cabinet I0 as shown at the right of Fig. 1, the opposite end ofleach of said shafts is re? duced and journaled in bushings identical to 55 to 53 inclusive, -which are secured in left hand end o'f cabinet I0. shafts extend through and project from the cab- Knurled .knobs 59, 60 and 6I and 80 are secured on reduced projecting ends of said shafts 5I, 52, 53

and 54 respectively to ,provide for convenient and selective manual rotation thereof.

As clearly shown in Figs. 1, 2 and 3 the upperi used in photography. Said film belt 62 has its opposite ends wedged in longitudinal diametrically extending recesses. One of said recesses is formed in shaft 35 and the other in shaft 54 as clearly shown in cross-section in Fig. 2, this preventing complete detachment of either end of the belt 62 when it is wound in the opposite direction. Flanges 63 are mounted on shaft 35 to guide said belt when the same is wound or unwound. Similar guide flanges 63' are mounted for similar purpose on lower shaft 54.

Belt 62 is composed of two separate strips of transparent film and which are attached together along their adjacent edges by a'binding adhesive tape or strip 62a.

Belt 62, which is designated the yellow color band, has along its edge adjacent the cabinet wall a plurality of substantially rectangular adjacent vertically alined areas, each area extending to the right a short distance, the edge of said yellow area being indicated by the reference numeral 62h, which line 62h is substantially opposite a point midway between viewing windows 2I and 22. Each of the yellow lareas on belt 62 viewable through window 2l is of a differentA .from the actual photographic illm' negative. More specically, the uppermost area of said row of color areas on said band 62 has a density of ten percent yellow color; the second and next lower area has a. twenty percent density of yellow; the third has a thirty percent density of yelow, and so on so that each next adjacent area has a color density ten percent greater in the same color as the one immediately above it, there being ten such areas.A The density color designated by percentage as indicated is of the same densltyand standard as known in the color reproduction art as applied to particular areas of color pictures, etc.

A similarly alined row of yellow areas of varying densities is borne by belt 62 upon areas thereof viewable through window 26, namely, be-

tween the vertical lines 62o and 62d, each of the respective areas being correspondinglypositioned with respect to the areas at the left edge of belt 62.

The right hand portion of the belt 62, which is viewable through windows 26 and 21 is composed oi a negative film portion 64 opposite window .26 from which the yellow ar as of belt 62 are transferred. The adjacent in egral strip oi' positive film 64a viewable through window 21, is the positive photographic film made from negative strip 66. The positive strip or portion 66a which is viewable through window 21, has indicia to indicate density, which indicia are placed identically and in corresponding positions to the percentage indicia at the extreme left of said color belt 62.

` j positive film to be employed in the process for reproducing the particular shade of yellow then presented to the viewer.

Belt 66, which is the red color band of flexible nlm material, has its opposite ends attaclied to and wound upon shafts 36 and 66 respectively. said color band 65 being immediately below and behind color band 62. Red color belt 66 hasl two rows of areas of red, one vertical row of red areas being at the left of said belt and viewable through window 22, and the second vertical row of red areas being viewable through window 26, the portions between said two rows of red areas being transparent photographic lm. Each area in each row is of dierent density, namely, the first and uppermost being of ten percent density of red, the second and next adjacent being of twenty percent density, the lowermost area thereon beingv of one hundred percentdensity of red. Said red color band 65 is so positioned and guided for rotative movement on its shafts 36 and 53 respectively by means of guide anges 66 so that the left row of its areas of red colorA sponding positive film 65h, said belts being of the.

same length and similarly attached upon aforesaid rotatable shafts 66 and 63. The negative portion 66a oi said belt is viewable through window 28 and the positive portion 66h is viewable through window 29.

In like manner and as explained in respect to the yellow color band the density of a given red area of said density isreadable through window 22 and simultaneously there will be presented the corresponding and proper light density area with its indicia through negative window 26. also simultaneously presenting the proper and corresponding positive light density and indicia through window 26. The presentation of the color area desired through window 22, which is matched .by the operator with the color area of the work of art sought to be reproduced, thereby gives instantly to the operator the proper iight density of the negative to beemployed and the proper light density of the positive tovbe employed in order to correctly and accurately reproduce the color area of a given work of art.

Reference numeral 61 is the blue color belt which has its opposite ends releasably attached to upper shaft 61 and lower shaft 6,2, which places said belt as the third in position and in such a position that the extreme edge to the viewers left looking at Fig. 1 or 3 is maintained immediately to the left of ,window 26, said belt extending to the right to a positionfimmedialy to the right of window 6i. Said belt 61 is guided for vertical movementby suitable guide flanges 66 which are similar in construction to flanges and 66, all of which areshown' in Fig. 3. The blue color belt 61 consists of flexible photographic iilm material having on the left hand edge thereof and viewable through window 26, a -vertical row of ten 'diiferent adjacent. color areas of blue. each area being of a diiferentydensity of blue and'more particularly the uppe density of blue, the secoy d being twenty percent ost being ten percent density of blue; the third being thirty percent density of blue, and so on, the last andlowerrnost area being solid blue or one hundred percent density of blue. A second vertical row of adjacent blue areas, oi' identical densities in corresponding horizontal planes is borne by belt 61 at a position viewable through window 26.

r The right hand portion oi' belt 61 is composed of a vertical negative photographic illm strip 66 extending from one end of said belt to the other and secured to color belt 61 by suitable binding tape (not shown), said negative being viewable through window 60, and the outer edge of belt 61 is composed of integral positive photographie iilm-strip 10 which is reproduced from strip 66. As stated before, negative illm strip 66 has indicia thereon so positioned as to indicate the proper' light density to be used in the making of the negative illm to accurately correspond to and reproduce the particular blue color area which is viewed tll'ough window 23. Likewise the posy itive strip 10 has indicia properly placed thereon to show the correct light density. of each area of the lm strip and which is to be used in process of producing the halftones or printing plates which in turn will'reproduce the particular area and density of blue which has been matched and viewed through window 23.` The fourth and innermost belt 1i is the black color belt which has one end attached and windable upon upper shaft 38 and its other end attached to and windable upon lower shaft 6I. Belt 1I is constructed similarly to the yellow, red and bluebelts before described and has along its left hand edge, and viewablev through window 24, one row of adjacent light color areas in vertical alignment, the uppermost color area being of ten percent density of black; thenext adjacent black color area being of twenty percent density of black, and so on 5 gradually, the lowermost color area being of one hundred-percent density of black. A second vertical row of black color areas is borne by belt 1I at a position so ythat same is viewable through window 25, said areas being of density and horilo zontal position `corresponding to said first mentioned row of black areas.

The right hand portion of belt 1I comprises a photographic negative film strip 12 which has its edge secured to the adjacent edge of belt 1l by a suitable binding strip, (not shown), and which extends from one end of the belt to the other and which negative portion is composed of a plurality of photographic negative areas, each of different light density, the uppermost 2o being one hundred percent negative density, the

next adjacent being ninety percent negative density, and so on, the lowermost of the ten areas having no black color whatever and its density being indicated by zero. The outer and right hand edge portion of black belt-1| is composed of a photographic positive strip 13 which is made from negative strip 12 and which extends from one end of the belt to the other and which has ten adjacent areas of positive film each of different light density, the density of the uppermost being zero,` the next adjacent being ten percent positive light density, the third being twenty percent positive light density, and so on, the lowermost being one hundred percent positive light density.

As clearly shown in cross sectional view of Fig.

2, I provide a pair of spaced apart parallel tension rods 15 and 16 respectively which extend from one side wall of the cabinet to the other, these rods being adapted to hold a portion of eaclf of the color and photographic film belts in a position immediately adjacent the respective viewing windows heretofore described, as clearly shown in Fig. 2. Tension rod 15 has its ends secured in corresponding eyelet ends of resilient springs 11 which preferably are of clock spring steel which extend outwardly and have their respective opposite ends secured to the respective opposite ends of cabinet I0 by means of suitable screws 18 as shown in the drawings. Tension rod 16 is likewise mounted. having its ends secured in eyelet ends of a pair of tension springs 19 Whose lower ends are likewise secured to the cabinet wall by a suitable screw. It will be noted that the position of the rods is such that a portion oi the respective color and photographic film belts will be held substantially flat against the entire area of the respective viewing windows in front of the cabinet. l

Having described the structure of the preferred K form of my device and its quick and convenient operation, it will be apparent from the foregoing that I have provided an entirely novel device or apparatus for determining and measuring the density of color, as well as the'density of light oi` various works of art and for quickly presenting #to view nearly iive thousand combinations or tones of color for quick comparison with works of art, and for quicl: indication and disclosure of both the density of respective colors to be employed and-of the correct density of the negative which is to be employed in the printing plate producingprocess which will correctly reproduce the "density of respective colors or tone of colors 76 desired. Fhiawarethat numerous details of particular form described in the foregoing.

construction may be varied in wide range without departing from the principles of my invention and I do not desire my invention to be limited to the I claim as my invention: 5 l. In a device ofthe class described for ascertaining the densities of colors in a work of art, a cabinet; a light source in said cabinet; a plurality of spaced apart substantially horizontal shafts rotatably mounted in said cabinet; said lo cabinet having a plurality of spaced apart windows in substantial horizontal alignment in its forward wall; a plurality of flexible bands in said cabinet, each of said bands having its opposite ends attached to andl windable upon two of said l5 spaced apart shafts, each of said ,bands bearing` vertically aligned transparent color areas of graduated densities, said transparent color portions of all said bands being superimposed, the color areas constituting said superimposed band por-U20 tions being adapted to be selectively positioned adjacent to and for view through one of said windows; indicia on each band for indicating the densities of said color areas and viewable through other of said spaced apart windows; each 25 of said bands having mounted adjacent one edge thereof a negative film band having a plurality of vertically aligned negative areas of known, graduated light densities, a positive film band mounted on each pair of shafts adjacent each of said 30 negative lm bands and adapted to move parallel with said color band and said negative fllm band, said positive film band having in vertical alignment a plurality of positive film areas of varied light densities; indicia adapted to be disposed 35 before certain of said windows on each of said negative portions and on each of said positive portions indicating the densities of said respective film areas simultaneously presented to view, and means for manually and selectively moving said bands to present desired color areas or com- 0 binations of color areas to view, the selective rotation of said shafts permitting selective superpositioni'ng of the various color areas on said superimposed band portions to cause the selected superimposed color areas to present to view a de- 45 sired blended color area, each color area on said color bands being in horizontal alignment with negative and positive iilm band areas which film band areas indicate the desirable film used in reproducing such horizontally aligned color area. 50

2. In a device of the class described for ascertaining the densities of respective colors in a.work of art, a cabinet; a plurality of spaced apart shafts rotatably mounted in said cabinet; said cabinet having a plurality of spaced apart win- 55 dows in substantial horizontal alignment in one wall thereof; a plurality of flexiblebands in said cabinet, each of said bands having its opposite ends attached to and windable upon two of said spaced apart shafts, each of said bands bearing 60 a plurality of adjacent vertically aligned transparent color areas of graduated densities, the color areas of said bands being positioned behind a plurality of said windows, a portion of all the color areas of each band being superposed over 65 the color areas of the other bands and so positioned as to be presentable to view through one of said windows; indicia on the non-superposed portion of each band for indicating the densities of the respective color areas in horizontal align- 70 ment therewith, and means for manually and selectively moving said bands to selectively position desired color areas to viewbefore one of said windows and to sirnulmnepglypresent said indicia to view before another of 'said windows. 75

3. In a device for measuring the densities of respective color areas of a work of art and for determining the density of film to be employed in reproducing said color areas, a cabinet; a plurality of spaced apart rotatable shafts mounted in said cabinet in parallel and horizontal relation, one-half of said shafts being in the upper part of said cabinet and the other half below the same; a plurality of spaced apart horizontally aligned viewing 'windows in the front of said cabinet; a plurality of belts, each belt having one end attached to one of said upper shafts and the other end attached to one of said lower shafts, each of said belts having a plurality of color areas of varying color density, all areas on the same belt being of various densities of the same color, said belts being disposed behind said windows respectively; all of said belts having one side portion in superposed overlapping position relative to each other and disposed behind one of said viewing windows, each successive belt from the ,foremost to the rearmost having the opposite side portion extended a greater distance than the forward adjacent belt, indicia on the extended portions of each of said belts indicative oi the density of the color area in horizontal alignment on the same belt, the selective rotation of said shafts permitting selective positioning of desired superposed color areas before one of said windows and simultaneously positioning the indicia-bearing belt portions before other of said windows.

4. In a device for measuring the densities of respective color areas of a work of art and for determining the light density of lm to be employed in reproducing said color areas, a cabinet; a light in said cabinet; a plurality of spaced-apart rotatable shafts mounted in said cabinet in parallel and substantiallyhorizontal relation, onehalf of said shafts being in the upper portion of said cabinet and the other half therebelow; a plurality of spaced apart substantially aligned viewing windows in the front of said cabinet; a plurality of belts each having one end thereof attached to one of said upper shafts and the other end attached to one of said lower shafts, each of said belts having a plurality of adjacent vertically aligned light pervious color areas of graduated densities said belts having their color area portions in superposed relation, said superposed belt portions being positioned behind one of said windows, each of said belts having another portion positioned behind another of said windows, indicia. on said last-mentioned portion of each of said belts indicative of the densities of the color areas in horizontal alignment therewith and borne by the same belt; said belts being selectively movable to present any of the color areas of one or more of said belts to view through one of said viewing windows and to simultaneously present before other of said windows the indicia indicative of the densities of the color areas positioned behind another of the viewing windows.

5. In a device for ascertaining the color densities of colors in a work of art, a plurality of flexible windable bands mounted for longitudinal movement adapted to be selectively moved to present portions thereof at certain viewing points; each band comprising a color bearing portion andan integral laterally extending side portion the color bearing portions being in SuDel'DOSed relation; a plurality of aligned primary Vcolor areas on each of said windable flexible bands. each area being of different and known density;

indicia on the laterally extending portion of each of said bands to indicate the color density of the aligned color areas respectively; a plurality of shafts on which said bands are mounted for winding movement and adapted to move said bands longitudinally; means providing for selective rotation of said shafts to wind said bands to position any of the color areas of one or more of said bands at a common viewing point and to simultaneously present said density-indicating indicia to view at other viewing points; and artificial lighting means behind said bands and visible through said windows and through said color areas to facilitate matching a colored area.

6. In a device of theclass described, a mounting shell having a plurality of spaced apart windows therein; a plurality of rollers journalled in said shell below and above said windows and' consisting of two or more pairs of rollers; a flexible band attached to and windable on each pair of said rollers, each pair of rollers comprising one upper. and one lower roller, each of said bands having a plurality of color areas of graduated densities thereon, a portion of each of said bands being superimposed upon portions of the other of said bands, said superposed portions being positioned before one of said windows, indicia on each band adjacent one edge thereof to indicate the respective densities of the color areas thereon, said indieiabeing simultaneously disposed before other of said windows, a exible film band on each of said pairl of upper and lower rollers, each said film band being composed of graduated negativefilm areas and graduated positive film areas which are horizontally aligned with color areas on said color band of corresponding densities; and indicia on each of said fllm bands indicative of the respective densities of the negative and positive areas of said fllmbands respectively, which are presented to view simultaneously with said respective color areas.

7. In a device for ascertaining the densities of colors in a work 4of art, a plurality of rotatably mounted shafts, a wall member having a plurality of horizontally aligned window openings, a plurality of flexible bands mounted on said shafts for winding and longitudinal movement, said bands having color portions thereof superposed;

Y a plurality of graduated color areas on the superposed portion of each of said bands, each color area being of a known density; indicia on each of said bands to indicate the density of each of said color areas; each of said bands having a longitudinallyl extending portion comprising a pluralityof Vnegative illm areas, each of said lm areas being oi' a different and known density; said bandsbelng movable longitudinally to present to view through one of said window openings and at a common point various combinations of superposed color areas, and simultaneously presenting to' view through certain of said window openings film areas bearing indicia thereon; ar-

tincial lighting means behind said color-bearing areas of said color bands to facilitate viewing thereof, and a exible band secured along one lateral edge of each of said color area bearing bands and windable therewith, said exible band having positive film areas thereon and bearing .indicia to indicate the proper positivelmtobeusedinreproducingthesuperposed color areas simultaneously presented to view.

ROBERT HACKAY. 

